The present invention relates to a soil modifying machine for modifying or improving soil in a state of clay which is obtained by condensation and dewatering of muddy water generated at a crushing field, a shield-type tunnel excavating field or the like, such a modified soil being thereafter recycled as backfill (soil to be refilled) or roadbed material.
Further, it is first to be noted that although the term xe2x80x9cmodify (modification or modified)xe2x80x9d used herein may be substituted with xe2x80x9cimprovexe2x80x9d or xe2x80x9camelioratexe2x80x9d, the meaning thereof is to modify (improve or ameliorate) nature, form quality or the like of a soil.
For example, Japanese Patent Laid-open (KOKAI) Publication No. HEI 11-169739 proposes such a soil modifying machine.
This soil modifying machine generally comprises, as shown in FIG. 33, a machine body, not shown, a mixer 1, a modified soil conveyer 2, a soil conveyer 3, a soil conditioner supply device 4 and a soil hopper 5. In a such soil modifying machine, a soil to be modified 6, e.g., raw soil in the soil hopper 5 is conveyed to the mixer 1 through the material soil conveyer 3 and a soil conditioner is supplied from the soil conditioner supply device 4 to the soil 6 on the way of being conveyed by the soil conveyer 3. Thereafter, the soil 6 and the soil conditioner is supplied to the mixer 1 so as to be crushed and mixed, and the thus modified soil 7 is discharged out of the machine body by means of the modified soil conveyer 2.
In such a soil modifying machine, the mixer 1 has an outer case (or housing) 10 in which a soil cutter cutting) device 11 as a primary mixer and a plurality of impact hammers (rotors having rotators) 12 are disposed so that the soil 6 conveyed by the soil conveyer 3 is cut off and dropped down by the soil cutter device 11 towards the impact hammers 12, and such soil and soil conditioner are crushed and then mixed by the impact hammers 12, thus performing the soil modification. The modified soil 7 is dropped down on the modified soil conveyer 2 through a discharge port 8.
Incidentally, in the soil crushing field or site, raw stones which are collected from a mountain or the like, are crushed by a crusher, and mud component or like adhering or sticking to the crushed stones are washed and removed so that the crushed stones can be utilized as aggregate.
The mud component removed in the above process is in a state of muddy water, which is then condensed and dewatered by a dehydrating (dewatering) press into a soil in the form of clay called as dewatered cake, which is then treated. When the dewatered cake is dried, fine particles scatter from its surface, and when the dewatered cake is wetted by rain water or like, it returns to the original muddy state.
As mentioned above, the dewatered cake has a low strength, and hence, in a case where such dewatered cake is recycled as backfill or roadbed material, the fine particles thereof will be scattered on sunny days or will be wet and flowed on rainy days, thus being inconvenient. Accordingly, it is difficult to recycle the dewatered cake as the backfill or roadbed material, and hence, such dewatered cake is left as it is in the raw stone crushing filed or site in a mountain.
The inventors of the subject application have tried to modify the soil condition by using a conventional soil modifying machine for recycling the dewatered cake as backfill or roadbed material, it was impossible to modify the soil condition to an extent suitable for recycling the dewatered cake as the backfill or roadbed material until the dewatered cake is very finely crushed and mixed with a solidifying agent because the dewatered cake has a low strength and is composed of a fine particle soil.
Through the research and experiment of the inventors, thereafter, the following matters were found out.
The soil cutter device 11 of the mixer 1 described above has a structure, as shown in FIG. 34A, that a plurality of cutters 14, each having a long scale, are mounted around a rotational shaft 13 so as to extend radially and to form widened V-shaped spaces 15 between the adjacent cutters 14 and the rotational shaft 13, respectively. When the rotational shaft 13 is rotated, the cutters 14 are also rotated to thereby cut off the soil 6 conveyed through the soil conveyer 3.
During the above cutting operation, when lump of clay 16 which cannot be cut by the cutter 14 exists in the soil 6, as shown in FIG. 34A, the cutter 14 which collides with the clay lump 16, is rotated while pushing the clay lump 16 into the material soil 6 as shown in FIGS. 34B and 34C and passes the clay lump 16 without cutting it. Thereafter, as shown in FIG. 34D, the next cutter 14 digs out the clay lump 16 and sputter it in a direction of the preceding cutter 14 into the V-shaped space 15 between this cutter 14 and the preceding cutter 14. When the cutter 14 is further rotated, the clay lump 16 between the space 15 drops down towards the impact hammers 12 as shown in FIG. 33.
As mentioned hereinbefore, when the soil cutter device 11 of the conventional structure is utilized, the lump of clay 16 which cannot be cut off by the cutter may fall downward as it is towards the impact hammers 12, there increases a possibility of the clay lump having a large diameter being mixed with the cut soil 6.
The clay lump having a large particle (soil) diameter has a worse infiltration of the soil conditioner. That is, in such a clay lump, even if the soil conditioner adheres to the outer surface of the clay lump, the soil conditioner hardly infiltrates thereinto, and hence, the inside central portion of the clay lump will maintain its clay state. As a result, in a case where the clay lump having a large diameter is mixed with the raw soil at a large mixing ratio, the soil conditioner cannot be sufficiently mixed with the soil, and hence, the modified soil which can be recycled as the backfill or roadbed material will not be obtainable.
Furthermore, in the conventional structure, the impact hammer 12 comprises a central rotational shaft 17 and four hammer pieces (blades) 18 mounted thereon so as to extend radially, each hammer pieces 18 being a forged product in a fist-like shape. Because of such a structure, the hammer piece 18 has a not so-large beating surface for giving an impact to the materials to be mixed (soil to be modified and soil conditioner), and moreover, since the beating surface is curved, the materials will not be fully crushed by the impact, and the dewatered cake will not be made fine, thus maintaining a large percentage of existing clay lump having a large diameter to be mixed.
Accordingly, in this case, as like as the aforementioned case, the soil conditioner cannot be sufficiently mixed with the soil to be modified, and hence, the modified soil which can be recycled as the backfill or roadbed material will not be obtainable.
An object of the present invention is to substantially eliminate defects or drawbacks encountered in the prior art mentioned above and to provide a soil modifying machine for obtaining a modified soil which can be recycled as backfill or roadbed material by mixing soil in the form of clay such as dewatered cake and a soil conditioner.
The inventors of the subject application have searched and experienced in view of the prior art mentioned above and found out that the soil could be finely granulated by improving a shape of a soil cutter device of a mixer to be a modified soil which can be recycled as backfill or roadbed material.
Further, the inventors have found out that the soil could be finely granulated by improving a shape of an impact hammer of a mixer to be a modified soil which can be recycled as backfill or roadbed material.
Furthermore, the inventors have also found out that the once modified soil can be further finely granulated by again mixing it by another mixer disposed downstream side of the first mentioned mixer to thereby be a modified soil which can be effectively recycled as backfill or roadbed material.
The above and other objects can hence be achieved according to the present invention by providing, in one aspect, a soil modifying machine having a machine body to which are disposed a soil hopper, a material soil conveyer for conveying a soil to be modified from the soil hopper, a soil conditioner supply device for supplying a soil conditioner to the soil and a mixer for crushing and mixing the conveyed soil and the soil conditioner to obtain a modified soil, the soil modifying machine being characterized in that the mixer is provided with a soil cutter device and a impact hammer and the soil cutter device comprises a drum and a cutter mounted to an outer peripheral surface of the drum.
According to this structure, at the time when the drum is rotated and the soil conveyed by the soil conveyer is cut off by the cutter and then supplied to the impact hammer, the soil lump having a particle diameter larger than the distance between the outer peripheral surface of the drum and the conveying surface of the soil conveyer cannot be supplied to the impact hammer.
Accordingly, even in the case where the soil lump having a large particle diameter is contained in the material soil, the material soil can be finely granulated to be a modified soil and the soil conditioner can fully infiltrate into the soil, thus improving the soil modifying ability. Thus, the soil in the shape of clay can be recycled as backfill or roadbed material.
In the above aspect the cutter has a height projecting from the outer peripheral surface of the drum by a length substantially equal to or less than a target particle diameter of the soil to be modified and a minimum distance between the outer peripheral surface of the drum and a conveying surface of the material soil conveyer is substantially equal to the target particle diameter.
According to this structure, since the soil having a particle diameter substantially the same as the target particle diameter of the soil to be modified can be supplied to the impact hammer, the modified soil having a predetermined target particle diameter can be obtained, and hence, the desired modifying effects can be achieved.
Furthermore, the cutter is disposed obliquely with respect to a direction parallel to an axis of the drum.
According to this structure, when the soil to be modified is cut by the cutter through the rotation of the drum, the cut-off soil is moved along the cutter. Therefore, the soil does not adhere to the cutter and, hence, the cutter does not clog with the soil.
According to a second aspect of the present invention, there is provided a soil modifying machine having a machine body to which are disposed a soil hopper, a soil conveyer for conveying a soil to be modified from the soil hopper, a soil conditioner supply device for supplying the soil conditioner to the soil and a mixer for crushing and mixing the conveyed soil and the soil conditioner to obtain a modified soil, the soil modifying machine being characterized in that the mixer is provided with a soil cutter device and a plurality of impact hammers and each of the impact hammers has a rotational shaft and a plurality of plate-shaped hammer pieces mounted to the rotational shaft.
According to this structure of the second aspect, since the impact hammer has a plate-like shape having a flat large beating surface, a good colliding efficiency with the material soil cut-off and dropped by the soil cutter can be obtained, and, hence, the particle size of the soil can be made fine. Therefore, even in a case where the soil lump having a large particle diameter is included in the soil to be modified, the particle diameter of the material soil can be made fine and the soil conditioner can fully infiltrate into the soil. Thus, the soil in the form of clay can be modified and effectively recycled as backfill or roadbed material.
In this structure, each of same hammer pieces may have a distal end in the shape of waveform.
According to this structure, since the distal end faces of the respective hammer pieces have waveformed shapes, when the material soil having a large particle size collides with this distal end portion, the soil to be modified collides only with the top portion thereof and does not collide with the bottom portion thereof, i.e. there is less area of the hammer distal end portion with which the soil collides, the colliding surface pressure (impact) is made large, so that the soil can be easily sheared and broken so as not to be spattered without being crushed and then effectively crushed.
Furthermore, since the respectively adjacent hammer pieces of the impact hammers are opposite to each other with a waveformed gap therebetween, the distance between the hammer pieces can be made small. Therefore, the soil passing between this gap is reduced in amount, thus the material soil crushing and mixing ability being improved.
According to the combined effects or functions mentioned above, the particle diameter of the soil can be surely made fine, thus remarkably improving the soil modifying effect.
According to the third aspect of the present invention, there is provided a soil modifying machine having a machine body to which are disposed a soil hopper, a soil conveyer for conveying a soil to be modified from the soil hopper, a soil conditioner supply device for supplying a soil conditioner to the soil, a mixer for crushing and mixing the conveyed soil and the soil conditioner to obtain a modified soil and a modified soil conveyer for conveying the modified soil, the soil modifying machine being characterized in that a rear side mixer is disposed for further crushing and mixing the modified soil discharged from the modified soil conveyer.
According to this structure, the soil and the soil conditioner are once crushed and mixed by the mixer to be the modified soil, which is thereafter further crushed and mixed by the rear side mixer to be the modified soil having a small particle size (diameter) even if the soil once modified by the mixer has a comparatively large particle size, whereby the soil conditioner can fully infiltrate into the soil to be modified, thus achieving an excellent soil modifying function. Therefore, the thus obtained modified soil can be effectively recycled as backfill or roadbed material.
Furthermore, there causes a case where the modified soil discharged from the mixer includes a large sized soil particle lump formed of a plurality of small sized ones at a time of being conveyed through the modified soil conveyer. However, in such a case, such large sized soil particles can be again crushed and mixed by the rear side mixer into small sized ones. Thus, the modified soil discharged from the rear side mixer is composed of small sized particles which can be surely visually observed as finely modified soil.
In this structure, the rear side mixer may be disposed at a discharge portion of the modified soil conveyer.
According to this structure, the rear side mixer can be moved together with the machine body.
Furthermore, in this structure, the rear side mixer is disposed independently of the machine body and disposed downstream side of the modified soil conveyer.
According to this structure, the rear side mixer can be arranged or removed in accordance with the condition of the soil to be modified.